Heat Exchangers (Crude Train) Restored to Design Parameters at a Refinery

Introduction

An Arabian gas liquefaction company shipped a titanium U-tube (hairpin) heat exchanger to Tube Tech’s UK research and development facility so that our dedicated team could remove calcium carbonate and tenacious silicate deposits from within the fragile tubes to restore heat transfer efficiency.

The Challenge

Titanium heat exchanger tubes typically have a long operational lifespan; however, they can still become blocked with fouling.
The exchanger, transported by sea to Tube Tech, was heavily blocked around the hairpins with calcium carbonate and tenacious silicate deposits which had contributed to a loss of heat transfer efficiency.
Tube Tech was contracted because the heat exchanger had very long tubes and our team has a reputation for being successful with challenging heat exchanger restoration projects.
Titanium tubes, while having excellent heat transfer properties, are thin and soft and require a higher level of care to prevent damage.

Refinery-Heat-Exchangers-Crude-Train-Before-Restore-to-Bare-Metal

The Solution

A multi-phase heat exchanger restoration approach was devised which started with a low-volume 60,000 PSI (4,000 BAR) water jetting system utilising intelligent metal lances which conformed to the shape of the tubes while drilling and jetting simultaneously.
As acid-type chemicals are not recommended on titanium, a biodegradable wash was used to remove traces of scale from the tube walls once a bore was created.
A miniature rotating darTT, unique to Tube Tech, was fired around the bend before a video probe returned a 3D image to confirm no damage to interior bores.
Careful use of bespoke jets and turbines and the lack of aggressive acids meant the titanium suffered no damage and was pristinely polished.

Tube Tech Comment

Scott Donson, Technical Director: “The hairpins were solidly blocked. This level of blockage and hardness factor has always previously meant a re-tube or full replacement. We had to take great care because the heat exchanger was titanium, perhaps the only one of its type that has been restored in this manner.”

Due to bespoke Intellectual Property being deployed, Tube Tech is happy to demonstrate and discuss the unique U-tube heat exchanger cleaning process if further information is required.

Client Comment

A spokesperson for the client said:

“We were very satisfied with the standard achieved. We had tried drilling, high-pressure jetting at 1,000BAR and various chemicals with no joy. Our objective was to unblock 5% of tubes to reach satisfactory performance.

Tube Tech achieved 7% and promised to attain 95%-plus if required. This avoided a full and expensive retube costing at least $250,000. We will have no hesitation in calling in Tube Tech again.”